- 3262 - STARS - in our Solar System? The inner solar system is a relatively tiny target, and even if Gliese 710 does send comets flying our way, it would take millions of additional years for these icy bodies to reach us. That should give any surviving future humans plenty of time to take action. And in the meantime, they can enjoy watching what may be one of the closest stellar flybys in the history of our solar system.
----------------------------- 3262 - STARS - in our Solar System?
- Astronomer Clyde Tombaugh discovered Pluto in 1930 by spending countless hours straining his eyes at a machine called a blink comparator. Using it, Tombaugh could flip rapidly back and forth between two images of the night sky taken at slightly different times.
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- A NASA citizen science project called “Backyard Worlds” asks volunteers to do much the same thing, if virtually. Volunteers comb through images of our celestial neighborhood, looking for new worlds near to us, just like Tombaugh. But instead of planets, they’re now looking for something even stranger. The search today is focused on a strange class of objects known as brown dwarfs, not quite planets, not quite stars.
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- The project has now released the most up-to-date map yet of brown dwarfs near Earth, something they say wouldn’t have been possible without the hard work of citizen scientists.
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- The map will help astronomers better understand how brown dwarfs form and evolve, and give researchers a better idea of the objects that populate the space just beyond our own solar system.
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- February, 1930, Tombaugh was flipping through recent images when he noticed a tiny dot that jumped back and forth, a sign that he’d found a nearby object. Further observational work ruled out other objects like asteroids, and the discovery of the onetime ninth planet was official. Today, Pluto has been demoted to the status of dwarf planet as we’ve discovered other objects like it in the Solar System.
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- We have not yet done discovering worlds in the outer reaches of the Solar System. A number of minor planets and other, “Kuiper Belt objects”, have been discovered in recent years. And some astronomers think there’s another large planet orbiting far out beyond Neptune, called “Planet Nine.”
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- Even further out in our celestial neighborhood there are likely to be a number of dim, mysterious objects known as “brown dwarfs“. Too large to be planets but not large enough to be stars, brown dwarfs are a strange kind of in-between object. They’re typically defined as being somewhere between 13 and 80 times the mass of Jupiter.
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- This map includes 525 brown dwarfs within 65 light-years of Earth, but more are surely waiting out there.
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- But brown dwarfs are very hard to find because they aren’t big enough to begin fusing hydrogen into helium. Brown dwarfs are often quite cool, meaning they don’t emit a lot of radiation that astronomers can pick up on.
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- Astronomers have found a wide variety of brown dwarfs that differ in terms of composition and internal activity. Still, many questions remain about how brown dwarfs form and what they look like.
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- That’s where citizen science comes in. Astronomers already have access to broad, high-resolution photos of nearly the entire night sky, thanks to data gathered from NASA’s Wide-field Infrared Survey Explorer, or WISE, spacecraft. Beginning in 2009, the satellite scanned the heavens in various infrared frequencies, and a second phase, dubbed NEOWISE, began in 2013.
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- Astronomers planned to follow up on anything interesting they spotted in the WISE images with other, more powerful infrared telescopes like the Spitzer Space Telescope. But they soon ran into a big problem: NASA was planning on shutting Spitzer down. To find anything, the scientists would need to move quickly.
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- They engaged citizen scientists early on to say ‘let’s try to find as many candidates as quickly as possible because we’re running out of time to do this with Spitzer. Without the citizen scientists, we would not have had all those candidates and enough time to do the follow-up.
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- Volunteers use an online tool to quickly flip through images of the night sky taken a short time apart. If they spot something moving, they’re able to alert astronomers, who’ll follow up on their work with more powerful observations using observatories.
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- Volunteers found dozens of new brown dwarfs candidates that scientists were able to follow up on with Spitzer to help create the new map. In all, the citizen scientists helped add 52 new brown dwarfs in just about a year.
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- Though Spitzer shut down in January of 2020, the astronomers were able to follow up on many promising candidates citizen scientists picked out. This led to the discovery of, among other things, a new class of brown dwarf, called “extreme T-type sub dwarfs“.
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- These objects are extremely old, in some cases around 10 billion years old. Other unique observations from the new map include the coldest known brown dwarf, a place where temperatures probably dip below the freezing point.
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- And other observations are still awaiting an explanation. One of the citizen scientists did find a really, really faint object that was just streaking across the sky. Further findings showed it was a very ancient cold brown dwarf composed largely of hydrogen, without the metals most other brown dwarfs have.
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- One volunteer even coded a tool, known as WiseView, that makes the process of discovering brown dwarfs far easier by allowing participants to flip easily back forth through the images.
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- Volunteers are invited to listen in on weekly telephone meetings between the scientists as well, where they discuss recent results and new objects to focus on.
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- Wandering stars pass through our solar system surprisingly often. Our sun has had close encounters with other stars in the past, and it’s due for a dangerously close one in the not-so-distant future.
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- Scholz’s Star and its binary brown dwarf fly by our solar system some 70,000 years ago
Every 50,000 years or so, a nomadic star passes near our solar system. Most brush by without incident. But, every once in a while, one comes so close that it gains a prominent place in Earth’s night sky, as well as knocks distant comets loose from their orbits.
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- The most famous of these stellar interlopers is called Scholz’s Star. This small binary star system was discovered in 2013. Its orbital path indicated that, about 70,000 years ago, it passed through the Oort Cloud, the extended sphere of icy bodies that surrounds the fringes of our solar system.
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- Some astronomers even think Scholz’s Star could have sent some of these objects tumbling into the inner solar system when it passed. The discovery of ‘Scholz’s Star occurred around Christmas 2013.
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- A wandering star passed within one light-year of the Sun roughly 70,000 years ago. At the time, modern humans were just beginning to migrate out of Africa, and Neanderthals were still sharing the planet with us.
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- In 2018, a team of researchers led by Coryn Bailer-Jones of the Max Planck Institute for Astronomy in Germany, used Gaia data to plot our Sun’s future meet-ups with other stars. They discovered nearly 700 stars that will pass within 15 light-years of our solar system over just the next 15 million years.
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- However, the vast majority of close encounters have yet to be discovered, the team suggests. But they suspect roughly 20 stars should pass within just a couple light-years of us every million years.
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- Statistically, most of those stars would pass the outer edge of our solar system.” That means encounters like the one with Scholz’s Star are common, but only a few are close enough to actually dislodge a significant number of comets,
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- A few stars should still come surprisingly close. And if a large, slow-moving star did pass through the edge of the Oort Cloud, it could really shake up the solar system.
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- Many nearby stars will pass close to the Oort Cloud, but only one will move through it. In about 1.35 million years, Gliese 710 likely will gravitationally perturb millions of comets, sending a sizable number on a potential collision course with Earth.
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- The ‘strongest disrupting encounter’ in history occurred when a massive star came steamrolling through the outer solar system is exactly what Gaia data show will happen less than 1.4 million years from now, according to a 2016 study. A star called ‘Gliese 710” will pass within 10,000 astronomical units, 1 AU is equal to the average Earth-Sun distance of 93 million miles. That’s well within the outer edge of the Oort Cloud.
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- At half the mass of the Sun, Gliese 710 is much larger than Scholz’s Star, which is just 15 percent the mass of the Sun. This means Gliese 710’s hulking gravity could potentially wreak havoc on the orbits of icy bodies in the Oort Cloud.
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- While Scholz’s Star was so tiny it would have been barely visible in the night sky, Gliese 710 is larger than our current closest neighbor, Proxima Centauri. So when Gliese 710 reaches its closest point to Earth, it will burn as a brilliant orange orb that will outshine every other star in our night sky.
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- This event could be the strongest disrupting encounter in the future and history of the solar system.
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- September 3, 2021 STARS - in our Solar System? 3262
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